Textile ply capable of absorbing sound waves

ABSTRACT

Textile ply formed by weaving yarns sheathed in a thermoplastic substance, said sheathed yarns being spaced apart from one another in both the warp and weft direction so as to form openings referred to as “intersection” openings arranged at the intersections between the warp yarns and weft yarns, said textile ply being intended to enable an absorption of sound waves, characterized in that it comprises in the warp direction and/or in the weft direction a plurality of groups of at least two sheathed yarns that are juxtaposed and that have the same weaving orientation, said yarns of one and the same group being locally spaced apart from one another and forming a plurality of openings referred to as “parallel” openings each comprising a shape and an angular orientation that are different from those of the openings referred to as “intersection” openings.

BACKGROUND

The present invention relates to the absorption of sound waves by means of textile plies suspended or stretched with a space formed behind, of at least a few millimeters and having no upper limit.

The invention more specifically aims at such open-worked textile plies formed by the weaving of coated yams, and having openings capable of trapping sound waves.

PRIOR ART

Generally, such textile plies have openings, to enable the sound wave to pass through the stretched textile ply.

Indeed, and as described in document FR-2875821, it is known to use glass yarns coated with a thermoplastic material to form an open-worked fabric having an openness factor in the range between 0.5 and 6%.

However, such a type of sound-absorbing fabric is defined by its openness factor. Thus, the openings are thus seen as through openings without considering their spatial orientation and their openness rate may be appreciated with a microscope. Further, it is also known to form a fabric with an openness rate predetermined by calendering of a fabric having a greater openness factor. Such a calendering results in flattening the fabric and accordingly in decreasing the spatial orientation of each opening.

Thus, such openings may be capable of absorbing sound waves having an incidence normal to the plane of the textile ply while appearing to be rather inefficient for sound waves having a low or grazing angle of incidence.

Further, prior art fabrics are characterized by their openness factor. This parameter is useful, but not sufficient to optimize the absorption performance of a fabric. Indeed, sound propagation in a volume is diffuse, and thus, by definition, formed of waves having a great variety of angles of incidence on the textile ply. Thus, sound waves having a normal incidence, that is, an angle of incidence close to 90° relative to the fabric plane, may cross conventional through openings of the fabrics only defined by their openness factor. However, such holes are not accessible to sound waves having a variety of orientations and angles of incidence.

Thus, the invention aims at generating ports into which sound waves having a variety of orientations and a low angle of incidence can penetrate and are no longer reflected by the textile ply.

DISCUSSION OF THE INVENTION

The invention thus relates to a textile ply formed by the weaving of yams coated with a thermoplastic substance, such coated yarns or groups of coated yams being spaced apart from one another in both the warp and weft direction to form openings referred to as “intersection” openings arranged at the intersections between warp yarns and weft yarns. Such a textile ply is intended to allow a sound wave absorption.

According to the invention, such a textile ply is characterized in that it comprises, in the warp and/or in the weft direction, a plurality of groups of at least two juxtaposed coated yams having a same weaving direction, such yams of a same group being locally spaced apart from each other and forming a plurality of openings referred to as “parallel” openings each having a shape and an angular orientation different from those of “inter-section” openings.

The “intersection” openings associated with the “parallel” openings provide a so-called “3-dimensional” porosity. Such ports having a variety of spatial orientations enable to efficiently absorb diffuse waves.

Such a “3-dimensional” porosity cannot be characterized by a simple openness factor measured with a microscope and seen in a plane. This is in particular due to the fact that the openness factor seen with the microscope with a normal incidence cannot take into account openings having grazing angles of incidence. To characterize such a 3D porosity and to take into account all openings, and in particular “parallel” openings, the air permeability of the textile ply may be measured. The sound wave being an air pressure wave, the permeability to air better represents the accessibility to sound waves in the 3 dimensions of space.

Advantageously, the textile ply may comprise in the warp and/or in the weft direction a number of yarns per centimeter in the range between 8 and 24, and more specifically in the range between 12 and 20.

In practice, the yams may comprise a core formed by strands made of a material selected from the group comprising polyester, polyamide, polyolefin, acrylic, vinyl, and glass.

Such materials are highly resistant and thus enable to ease the weaving of the textile ply, while guaranteeing an optimal mechanical behavior of the textile ply and a tearing resistance. Such materials also enable to from large textile plies, in particular capable of covering a ceiling or a wall by means of frames and of a peripheral stretching system such as straps or cables. They may also be used as acoustic baffles suspended to the ceiling.

According to a specific embodiment, the linear mass density of the yarn core may be in the range between 250 and 1,100 dtex.

Further, the yarns coated with the thermoplastic substance may have a linear mass density between 1,000 and 4,000 dtex.

Such characteristics indeed enable to provide the textile ply with a specific resistance measured according to standard ISO 9053, method A, or NF EN ISO 29053, method A, in the range between 100 and 1,100 N.s.m-3 or Pa.s.m-1 or also Rayls.

Advantageously, the thermoplastic substance of the coatings may be made of a material selected from the group comprising polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), silicones, acrylic, and polyurethane.

The use of a PVC coating advantageously enables to recycle the textile ply according to a currently used recycling process.

In practice, the thermoplastic substance of the coatings may be made of a material such as open-cell foam.

According to a specific embodiment, the textile ply may comprise, on at least one of its surfaces, an added layer of material taking part in the sound wave absorption.

Such a layer of material can thus be installed according to different methods such as for example flocking or pasting. The added layer of material may appear in the form of a nonwoven textile ply such as a felt, an open-cell foam or also hair.

Such a textile may reach alone a weighted sound absorption coefficient alpha w of at least 0.6 with an air gap of 10 cm behind it and capable of reaching 0.90 with added layers of material.

BRIEF DESCRIPTION OF THE DRAWINGS

The way to implement the present invention, as well as the resulting advantages, will better appear from the description of the following non-limiting embodiment, given as an indication, based on the accompanying drawings, among which:

FIGS. 1 and 2 show in front view, respectively a textile ply according to prior art and a textile ply according to the invention;

FIGS. 3 and 4 show, respectively, cross-section views of a textile ply according to prior art and of a textile ply according to the invention;

FIG. 5 shows in cross-section view a variation of coated yarns enabling to form a textile ply according to the invention;

FIGS. 6 and 7 respectively show cross-section views according to two variations of a textile ply according to the invention.

DETAILED DESCRIPTION

As already mentioned, the invention relates to a textile ply capable of absorbing sound waves and formed by the weaving of yams coated with a thermoplastic substance.

As shown in FIG. 1 and according to prior art, it is known to form such a textile ply 1 by the weaving of warp yams 2 and of weft yarns 4. As shown, such a textile ply 1 comprises through openings 6, 7 arranged at the intersections between warp yarns and weft yarns.

Further, and as shown in FIG. 2, a textile ply 10 according to the invention has warp yarns 12, 13, 22, 23 woven with weft yarns 14, 15 and openings 16, 17 arranged at the intersection between warp yarns and weft yarns. Such openings 16, 17 are thus called “intersection” openings.

Further, such a textile ply 10 also comprises openings referred to as “parallel” openings 18 and 19, arranged between two parallel juxtaposed warp yarns and having the same weaving direction. In other words, juxtaposed warp yams 12, 13 are maintained apart from each other during the operation of weaving of textile ply 10. Such openings 18 and 19 thus comprise a geometry and an angular arrangement different from “intersection” openings 16, 17.

Further, with a significant shrinkage, openings 18, 19 may orient substantially laterally to enable to capture grazing sound waves, that is, of low incidence relative to the surface of the textile ply.

As shown in FIG. 3 and according to prior art, the interstices between warp coated yarns 2 only generate “intersection” openings 6, 7. Such openings then enable to define a porosity defined by its openness factor without taking into account the spatial orientation of the openings. Such a porosity can thus be easily analyzed and quantified by means of a microscope.

On the contrary, according to the invention and as shown in FIG. 4, warp yams are arranged in groups of two juxtaposed yarns 12, 13 and 22, 23. The warp and weft yarns cross to form, on the one hand, “intersection” openings 17 to promote the absorption of sound waves with an angle of incidence relative to the surface of the textile ply close to the normal direction. On the other hand, the warp and weft yarns are locally spaced apart from each other to form openings referred to as “parallel” openings between two yams of same orientation.

Further, in a plane perpendicular to that of FIG. 4, the significant shrinkage of the warp yarns enables to orient “parallel” openings 18, 19 to make them accessible to waves having a low angle of incidence relative to the surface of the textile ply. The combination of these two effects enables to absorb sound waves having a variety of orientations and incidences relative to the textile ply surface.

Accordingly, the textile ply according to the invention enables to absorb sound waves having a variety of orientations and incidences both in the plane of FIG. 4 and in a plane perpendicular to the plane of FIG. 4 by means of “intersection” openings 16, 17 and of “parallel” openings 18, 19.

Further, as shown in FIG. 4, warp yarns 12, 13, 22, 23 may comprise a core 25 formed by strands 26 made of polyester. Core 25 is then covered with a thermoplastic coating 27 made of polyvinyl chloride (PVC).

According to another embodiment and as shown in FIG. 5, textile ply 30 may comprise warp yarns 32, 33 comprising a coating 37 made of a material of open-cell foam type. Such an embodiment then enables to provide textile ply 30 with an optimal sound wave absorption.

As shown in FIG. 6, textile ply 40 may also comprise a layer of material 41 added by projection. Layer 41 of material appears in the form of hair 44 bonded to upper crests 43 of the warp and weft yams of the textile ply. The bonding is indeed performed by means of glue pads 42 regularly distributed on upper crests 43 of the yarns by a method for projecting the hair into glue pads 42.

Hair 44 may in particular have a 20-μm diameter and a 200-μm length. Such a layer 41 of material thus enables to improve sound wave absorption.

Similarly and as shown in FIG. 7, textile ply 50 comprises a layer 51 of material added by pasting by means of glue pads 52 regularly arranged at the level of crests 53 of the warp and weft yarns of textile ply 50. Such a layer 51 of material may in particular be a nonwoven, such as felt or an open-cell foam sheet.

As appears from the foregoing, the textile ply according to the invention has many advantages, and in particular:

-   -   it enables to improve sound absorption by comprising openings         having different angular orientations;     -   it enables to use coated yams of significant linear mass density         having an optimal breakage resistance;     -   it enables to achieve a sound absorption on large surface areas,         and especially on ceilings;     -   it is very light, which also makes it easy and fast to remove. 

1. A textile ply formed by the weaving of yarns coated with a thermoplastic substance, said coated yarns being spaced apart from one another in both the warp and weft direction to form openings referred to as “intersection” openings arranged at the intersections between warp yarns and weft yarns, said textile ply being intended to allow a sound wave absorption, characterized in that it comprises, in the warp and/or in the weft direction, a plurality of groups of at least two juxtaposed coated yarns having a same weaving direction, such yarns of a same group being locally spaced apart from each other and forming a plurality of openings referred to as “parallel” openings, each having a shape and an angular orientation different from those of “intersection” openings.
 2. The textile ply of claim 1, characterized in that it comprises in the warp and/or in the weft direction a number of yarns per centimeter in the range between 8 and
 22. 3. The textile ply of claim 1, wherein the yarns comprise a core formed by strands made of a material selected from the group comprising polyester, polyamide, polyolefin, acrylic, vinyl, and glass.
 4. The textile ply of claim 3, characterized in that the linear mass density of the core of the yarns is in the range between 250 and 1,100 dtex.
 5. The textile ply of claim 1, characterized in that the linear mass density of the yarns coated with a thermoplastic substance is in the range between 1,000 and 4,000 dtex.
 6. The textile ply of claim 1, characterized in that it has a specific resistance in the range between 100 and 1,100 N.s.m-3.
 7. The textile ply of claim 1, characterized in that the thermoplastic substance of the coatings may be made of a material selected from the group comprising polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), silicones, acrylic, and polyurethane.
 8. The textile ply of claim 1, characterized in that the thermoplastic substance of the coatings is made of a material of open-cell foam type.
 9. The textile ply of claim 1, characterized in that it comprises, on at least one of its surfaces, an added layer of material taking part in the sound wave absorption. 